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Date: Mon, 18 Apr 2022 21:22:11 +0800
From: He Zhe <zhe.he@...driver.com>
To: catalin.marinas@....com, will@...nel.org, mark.rutland@....com,
tglx@...utronix.de, bp@...en8.de, dave.hansen@...ux.intel.com,
keescook@...omium.org, alexander.shishkin@...ux.intel.com,
jolsa@...nel.org, namhyung@...nel.org, benh@...nel.crashing.org,
paulus@...ba.org, borntraeger@...ux.ibm.com, svens@...ux.ibm.com,
hpa@...or.com
Cc: x86@...nel.org, linux-arm-kernel@...ts.infradead.org,
linuxppc-dev@...ts.ozlabs.org, linux-riscv@...ts.infradead.org,
linux-s390@...r.kernel.org, linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org, zhe.he@...driver.com
Subject: [PATCH RFC 2/8] arm64: stacktrace: Add arch_within_stack_frames
This function checks if the given address range crosses frame boundary.
It is based on the existing x86 algorithm, but implemented via stacktrace.
This can be tested by USERCOPY_STACK_FRAME_FROM and
USERCOPY_STACK_FRAME_TO in lkdtm.
Signed-off-by: He Zhe <zhe.he@...driver.com>
---
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/thread_info.h | 12 +++++
arch/arm64/kernel/stacktrace.c | 76 ++++++++++++++++++++++++++--
3 files changed, 85 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 57c4c995965f..0f52a83d7771 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -165,6 +165,7 @@ config ARM64
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_TRANSPARENT_HUGEPAGE
select HAVE_ARCH_VMAP_STACK
+ select HAVE_ARCH_WITHIN_STACK_FRAMES
select HAVE_ARM_SMCCC
select HAVE_ASM_MODVERSIONS
select HAVE_EBPF_JIT
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index e1317b7c4525..b839ad9f2248 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -58,6 +58,18 @@ void arch_setup_new_exec(void);
void arch_release_task_struct(struct task_struct *tsk);
int arch_dup_task_struct(struct task_struct *dst,
struct task_struct *src);
+/*
+ * Walks up the stack frames to make sure that the specified object is
+ * entirely contained by a single stack frame.
+ *
+ * Returns:
+ * GOOD_FRAME if within a frame
+ * BAD_STACK if placed across a frame boundary (or outside stack)
+ * NOT_STACK unable to determine (no frame pointers, etc)
+ */
+int arch_within_stack_frames(const void * const stack,
+ const void * const stackend,
+ const void *obj, unsigned long len);
#endif
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index e4103e085681..219b90c1de12 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -145,12 +145,17 @@ NOKPROBE_SYMBOL(unwind_frame);
static void notrace walk_stackframe(struct task_struct *tsk,
struct stackframe *frame,
- bool (*fn)(void *, unsigned long), void *data)
+ stack_trace_consume_fn fn, void *data)
{
+ struct frame_info fi;
+
while (1) {
int ret;
- if (!fn(data, frame->pc))
+ fi.pc = frame->pc;
+ fi.fp = frame->fp;
+ fi.prev_fp = frame->prev_fp;
+ if (!fn(data, &fi))
break;
ret = unwind_frame(tsk, frame);
if (ret < 0)
@@ -159,10 +164,10 @@ static void notrace walk_stackframe(struct task_struct *tsk,
}
NOKPROBE_SYMBOL(walk_stackframe);
-static bool dump_backtrace_entry(void *arg, unsigned long where)
+static bool dump_backtrace_entry(void *arg, struct frame_info *fi)
{
char *loglvl = arg;
- printk("%s %pSb\n", loglvl, (void *)where);
+ printk("%s %pSb\n", loglvl, (void *)fi->pc);
return true;
}
@@ -210,3 +215,66 @@ noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,
walk_stackframe(task, &frame, consume_entry, cookie);
}
+
+struct arch_stack_object {
+ unsigned long start;
+ unsigned long len;
+ int flag;
+};
+
+static bool arch_stack_object_check(void *data, struct frame_info *fi)
+{
+ struct arch_stack_object *obj = (struct arch_stack_object *)data;
+
+ /* Skip the frame of arch_within_stack_frames itself */
+ if (fi->prev_fp == 0)
+ return true;
+
+ /*
+ * low ----------------------------------------------> high
+ * [saved bp][saved ip][args][local vars][saved bp][saved ip]
+ * ^----------------^
+ * allow copies only within here
+ */
+ if (obj->start + obj->len <= fi->fp) {
+ obj->flag = obj->start >=
+ fi->prev_fp + 2 * sizeof(void *) ?
+ GOOD_FRAME : BAD_STACK;
+ return false;
+ } else
+ return true;
+}
+
+/*
+ * Walks up the stack frames to make sure that the specified object is
+ * entirely contained by a single stack frame.
+ *
+ * Returns:
+ * GOOD_FRAME if within a frame
+ * BAD_STACK if placed across a frame boundary (or outside stack)
+ * NOT_STACK unable to determine (no frame pointers, etc)
+ */
+int arch_within_stack_frames(const void * const stack,
+ const void * const stackend,
+ const void *obj, unsigned long len)
+{
+#if defined(CONFIG_FRAME_POINTER)
+ struct arch_stack_object object;
+ struct pt_regs regs;
+
+ if (__builtin_frame_address(1) == 0)
+ return NOT_STACK;
+
+ object.start = (unsigned long)obj;
+ object.len = len;
+ object.flag = NOT_STACK;
+
+ regs.regs[29] = (u64)__builtin_frame_address(1);
+
+ arch_stack_walk(arch_stack_object_check, (void *)&object, NULL, ®s);
+
+ return object.flag;
+#else
+ return NOT_STACK;
+#endif
+}
--
2.25.1
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